Atherosclerosis and its clinical consequences, coronary heart disease (CHD), stroke and peripheral vascular disease, represent a truly enormous burden to the health care systems of the industrialized world. In the United States alone, approximately 13 million patients have been diagnosed with CHD, and greater than one half million deaths are attributed to CHD each year. Further, this toll is expected to grow over the next quarter century as the average age of the population increases and as an epidemic in obesity and diabetes continues to grow.
Inhibition of cholesteryl ester transfer protein (CETP) is a promising new approach to reducing the incidence of atherosclerosis. Statins have been important in reducing the incidence of CHD by reducing LDL-cholesterol (the “bad cholesterol”), but are relatively ineffective at raising HDL-cholesterol (“the good cholesterol”). CETP inhibitors raise HDL-cholesterol and may also lower-LDL-cholesterol, and may therefore provide a potent new tool for reducing CHD and atherosclerosis in the general population. Combination therapy using CETP inhibitors and statins may also become a valuable tool for controlling both HDL and LDL levels, which may make it possible to both treat and prevent atherosclerosis, and perhaps even to reverse the formation of atherosclerotic plaques. Currently, Pfizer's torcetrapib is the only CETP inhibitor that is known to be in advanced Phase III clinical trials.
CETP inhibitors in general are very lipophilic. The compounds are generally nearly insoluble in water and in aqueous bodily fluids. Bioavailability of CETP inhibitors using conventional tablet formulations generally is poor. Oral formulations therefore need to be developed that will make the compounds bioavailable when they are administered to a patient. Liquid formulations of a particularly potent class of CETP inhibitors are described herein. The formulations disperse in water, resulting in higher absorption of the drug by the patient. These formulations are self-emulsifying formulations, yielding emulsions or microemulsions. The formulations are commonly referred to as self-emulsifying or self-microemulsifying drug delivery systems (SEDD's or SMEDD's).